The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses a transponder key ecu that stores the key codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the ecu sends a signal to the ecm to prohibit fuel delivery and ignition, effectively disabling the engine.

The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ecu. The ecu matches the key's id code with the vehicle's id code, which was previously registered in the ecu and then communicates the results to the ecm using sfi communication.
Engine immobiliser system
How to proceed with troubleshootingRear coil spring
Components
Removal
Hint:
Use the same procedures for the rh side and lh side.
The procedures listed below are for the lh side.
Remove rear wheel
Remove skid control sensor wire (for 2wd)
(see page bc-198)
Remove rear speed sensor lh (for 4wd) (see
page bc-205)
Disconnect ...
If your vehicle overheats
The following may indicate that your vehicle is overheating.
The high engine coolant temperature warning light Comes
on or a loss of engine power is experienced. (For example, the
vehicle speed does not increase.)
Steam comes out from under the hood.
Correction procedures
Stop ...
General maintenance (2006/01- )
Inspect drive belt (see page em-7)
Replace spark plugs (see page ig-7)
Replace air cleaner filter
Remove the air filter.
Visually check that the air filter is not excessively
damaged or oily.
Replace the air filter with a new one, if necessary.
Replace engine oil and oil fil ...